Apparatus for flashing gaseous discharge lamps



March 15, 1966 A. R. HALLAY APPARATUS FOR FLASHING GASEOUS DISCHARGE LAMPS 2 Sheets-Sheet 1 Filed April 11, 1963 March 15, 1966 A. R. HALLAY 3,240,992

APPARATUS FOR FLASHING GASEOUS DISCHARGE LAMPS Filed April 11 1965 2 Sheets-Sheet 2 INVENTOR. A/eYa Mfr/E War/lay,

AZ-Z'orney United States Patent 3,240,992 APPARATUS FOR FLASHHVG GASEOUS DISCHARGE LAMPS Alexander R. Halley, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Filed Apr. 11, 1963, Ser. No. 272,269 11 Claims. (Cl. 315254) The invention relates generally to electrical apparatus for flashing gaseous discharge lamps. More particularly, it relates to such apparatus wherein two or more gaseous discharge lamps are started and operated by the apparatus and at least one of the gaseous electric discharge lamps is flashed on and off in conjunction with one or more lamps operated at a steady output level.

Where luminous gaseous discharge lamps, such as neon tubes or fluorescent lamps, are used in signs or display systems, it is frequently desirable to flash one or more of the lamps on and oif to attract attention to the Sign or display system. In a commonly used apparatus, the gaseous discharge lamp is flashed on and otf by alternately energizing and deenergizing the primary circuit of the ballast transformer employed to provide the starting and operating potentials for the lamp. A disadvantage of such a conventional flashing arrangement is that separate ballast transformers are required for the lamp or lamps that are to be flashed and for the lamps that are to be continuously operated at a normal light output level. From an economic standpoint, it is desirable where possible to operate the flashing and nonflashing lamps from a single ballast transformer.

The need for separate ballast transformers may, of course, be eliminated by placing the switching device in the secondary circuit of the transformer. One of the principal difliculties with such an arrangement arises out of the high secondary voltages involved which Will vary depending upon particular neon tube applications and will range from 2,000 to 15,000 volts. At 15,000 volts open switching is not feasible because high voltage arcing presents a fire hazard. Although various switching arrangements have been proposed for the use in secondary circuits to minimize the effects of high voltage arcing, reliability and service life have not been entirely satisfactory since the switching elements employed are subjected to relatively high voltage.

In applications where the sign or display system is used at a location that is not readily accessible, it is usually desirable to locate the components of the flashing apparatus that require some periodic maintenance, such as the switching device, at a location where the component can be conveniently serviced. Where the component is a switching device connected in the secondary circuit of the ballast transformer, it is usually not desirable and generally not practicable to run long high voltage cables to place the component at a convenient location for servicing. For this reason and more particularly to improve the reliability and service life of the apparatus, it is desirable that the switching devices used in the flashing apparatus have relatively low volt-ampere ratings.

Accordingly, a general object of the present invention is to provide an improved apparatus for flashing one or more gaseous electric discharge lamps.

A more specific object of the present invention is to provide an improved apparatus for flashing one or more gaseous discharge lamps wherein the switching device utilized has a relatively low volt-ampere rating.

It is a further object of the present invention to provide an improved apparatus for flashing at least one gaseous discharge lamp in conjunction with one or more gaseous discharge lamps that are operated at normal light output level, all of the gaseous discharge lamps being operated from a single ballast transformer.

3,24%,992 Patented Mar. 15, 1966 Another object of the present invention is to provide an improved apparatus for operating and flashing gaseous discharge lamps wherein the switching element associated with the secondary circuit of a ballast transformer can be readily wired at locations remote from ballast transformer to facilitate servicing.

A further object of the invention is to provide an improved apparatus for operating flashing and non-flashing lamps from a single ballast transformer that will provide satisfactory and reliable service over extended periods of time.

In accordance with one form of the invention, I have provided an improved arrangement in which a flasher transformer having a relatively low volt-ampere rating is employed in conjuction with a ballast transformer to isolate a switching means from the high secondary voltage of the ballast transformer. The secondary winding of the flasher transformer is preferably loosely coupled with the primary to limit the secondary current. The primary winding of the flasher transformer is connected in circuit with the gaseous discharge lamp or lamps to be flashed. The switching element of the switching means is connected in the secondary circuit of the flasher transformer in order to alternately open and close the secondary circuit of the flasher transformer thereby to change the flasher transformer from a high impedance to a low impedance condition. The change of the flasher transformer from the high impedance to the low impedance condition of the secondary causes one or more of the gaseous discharge lamps to flash on and off.

According to one aspect of the invention, where the lamp is to be flashed in conjunction with one or more non-flashing lamps operated from a single ballast transformer, the primary winding of the flasher transformer is connected across the lamp to be flashed. Where a pair of lamps having different starting voltage requirements are to be flashed alternately, the primary winding of the flasher transformer may be connected in series circuit with the lamp having a lower impedance. In this arrangement the flashing gaseous discharge lamps are connected in parallel circuit branches which are connected in series circuit relation with the non-flashing lamp or lamps.

The improved arrangement makes it possible to use a switching element as a component of the switching means that is characterized by a relatively low volt-ampere rating. Thus, the reliability and service life of the switching means is significantly increased as compared with conventional systems employing switching elements subjected to the secondary voltage of the ballast transformers. Also, because of the low volt-ampere ratings of the switching elements that may be used in the improved arrangement, switching devices such as reed switches, thermal switches, clock motor driven rotary switches and other types of switching devices, can be employed to open and close the secondary circuit of the flasher transformer.

The subject matter which I regard as my invention is set forth in the appended claims. The invention itself, however, together with further objects and advantages thereof may be better understood by referring to the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a schematic circuit diagram of an ap paratus embodying one form of the invention in which one gaseous discharge lamp is flashed on and off and another gaseous discharge lamp is operated at a normal output level;

FIGURE 2 is a schematic circuit diagram of an apparatus embodying the invention wherein one gaseous discharge lamp is operated at a normal output level and a pair of gaseous discharge lamps are alternately flashed on and off; and

FIGURE 3 is a schematic illustration of another embodiment of the invention utilizing a motor-driven rotary switch to perform the switching function in the improved flashing arrangement.

In FIGURE 1 I have illustrated an apparatus for operating gaseous discharge lamps L at a normal light output level and for flashing a gaseous discharge lamp L The gaseous discharge lamps L L used in the illus trated embodiment of the invention were neon tubes. As used herein, a neon tube generally denotes a luminous gaseous discharge lamp comprised of a sealed glass tube with an electrode at each end and filled with a gas vapor or a mixture thereof, which may include neon, argon, helium, Xenon, krypton or mercury vapor. 7

When a specific starting potential is applied across the lamps L and L they will ignite and will glow in a color determined by the color of the tube and the particular gas or vapor or combinations thereof contained in the lamps L and L The requisite starting and operating potentials for lamps L and L are provided by a ballast transformer T As is shown schematically in FIGURE 1, the transformer T includes a primary winding P and a high leakage reactance secondary winding S inductively coupled with the primary winding P on a magnetic core 11. A magnetic shunt 12 provides a path for leakage fluX.

Although magnetic shunts were used to provide the desired leakage reactance, it will be understood, of course, that various other arrangements for providing flux leakage paths or shunts between the primary winding P and the secondary winding S may be employed. Depending upon the design of the particular ballast transformer, either air leakage paths, inserted shunts, or shunts integrally formed on the magnetic core 11 may be employed.

The primary winding P of the transformer T has a pair of leads or terminals 13, 14 for connection to a suitable alternating current supply. Lamps L and L are connected in circuit with the apparatus 10 by means of the leads or terminals 15, 16 and 17. The center tap 18 of the high leakage reactance secondary Winding S of the transformer T is connected in circuit with a ground G to reduce the secondary voltage to ground.

In accordance with the improved arrangement of the invention, a flasher transformer T has a primary winding P that is connected in circuit across the flashing gaseous discharge lamp L and inductively coupled with a secondary winding S on a magnetic core 20. In the embodiment of the invention shown in FIGURE 1, I have employed a reed switch 21 and a coil 22. The flashing circuit arrangement is more fully described and claimed in an application (3D2502) of Gordon M. Bell filed concurrently with the present application and assigned to the same assignee as the present application.

The reed switch 21 includes a pair of switching contacts 23, 24. When the apparatus 10 is initially energized, the reed switch 21 is normally in the open condition as shown. When the voltage across the coil 22 reaches a predetermined level as determined by the charge on capacitor C the switching contacts 23, 24 are closed to short the secondary circuit of the flasher transformer T The switching contacts 23, 24 are again opened when voltage across the coil 22 falls off as capacitor C discharges.

Resistor R and capacitor C are connected across the switching contacts 23, 24 to prevent the switching contacts 23, 24 from arcing. It will be noted that the capacitor C is charged with a DC. voltage through a diode D which is connected in circuit with a voltage dropping resistor R The rate at which the gaseous discharge lamp L is flashed on and off is determined by the frequency at which the capacitor C is charged to the voltage level required for coil 22 to close the switching contacts 23, 24 and is discharged to cause the contacts 23, 24 to open.

The apparatus 10 operates from the power supplied to the ballast transformer T When input terminals 13, 14 of the primary winding P are energized from a suitable alternating current source, the open circuit voltage is initially applied across gaseous dicharge lamps L and L since during the initial starting condition the secondary circuit of the transformer T is open, and the transformer T presents a high impedance. Consequently, the open circuit voltage is applied across leads 15 and 17 to ignite gaseous discharge lamps L and L and current flows through the lamps L and L and the dropping resistor R A unidirectional charging current is supplied to capacitor C When the capacitor C charges to a predetermined level and discharges through the coil 22 to provide the pull-in ampere-turns, the switching contacts 23, 24 close. The reactor or transformer T now presents a low impedance thereby causing the secondary of the ballast transformer T to shunt gaseous discharge lamp L therby extinguishing lamp L When lamp L does not support any current flow, there is no current flow through the dropping resistor R As capacitor C discharges through coil 22, the coil current falls 01f. When the coil current reaches a certain level, the switching contacts 23, 24 are opened, and the reactor or transformer T reverts to its high impedance condition. Thus, lamp L is again flashed on, and current flows through the dropping resistor R to start another charging cycle on the capacitor C The flashing cycle repeats itself at a frequency which is determined by the rate at which the capacitor C is charged and discharged to close and open switching contacts 23 and 24.

Referring now to FIGURE 2, I have illustrated therein a schematic circuit diagram of an apparatus 30 for operating a gaseous discharge lamp L at its normal luminous output level and for-flashing a pair of gaseous discharge lamps L, and L In the embodiment of the invention reduced to practice, as will be hereinafter more fully described, gaseous discharge lamp L; was a white neon tube, gaseous discharge lamp L, was a green tube having a lower operating voltage than the lamp L and gaseous discharge lamp L was a red neon tube, the green and red neon tubes being alternately flashed on and ofl.

As in the other embodiments of the invention, the starting and operating potentials for the gaseous discharge lamps L L and L were provided by a high leakage reactance type of ballast transformer T Transformer T includes a primary Winding P having terminals or leads 31, 32 adapted for connection to an alternating current supply and a secondary winding S inductively coupled therewith on a magnetic core 33. A path for leakage flux was provided by magnetic shunts 34 interposed between the primary winding P and the secondary winding S In order to reduce the secondary voltage to ground, the center tap 35 of the secondary winding S was connected to a ground G It will be noted that in this embodiment of the invention the primary winding P of the flasher transformer T is connected in series circuit relation with a flashing gaseous discharge lamp L which has the lower impedance. The switching means used to open and close the secondary circuit of the flasher transformer T is essentially similar to the one used in the other illustrated embodiments of the invention. It includes a reed switch 36 having a coil 37 and a pair of switching contacts 38, 39, a serially connected resistor R and capacitor C which prevent contacts 38, 39 from arcing, a capacitor C a diode D and a resistor R The resistor R is a voltage dropping impedance element across which a voltage is developed when current flows through the gaseous discharge lamp L The diode D rectifies the voltage across the resistor R so that capacitor C is charged with a unidirectional current.

Preferably, secondary winding 8.; of the flasher transformer T is loosely coupled with the primary winding P on a magnetic core 40. With a loosely coupled secondary winding S it is possible to limit the current flowing through the reed switch 21 during the interval the switching contacts 23, 24 are closed and further reduce the voltampere rating of the switching device. For example, in

5 the embodiment of the invention actually reduced to practice, the reed switch 21 used has a rating of 15 voltamperes.

As is shown in FIGURE 2, lead 41 connects lamp L in circuit with the secondary winding S Lead 42 joins lamp L in series circuit relation with the primary winding P in one parallel circuit branch while lead 43 joins lamp L in the other parallel circuit branch. In this circuit configuration, lamp L3 is operated at a steady light output level, and lamps L and L are alternately flashed 011 and on.

When apparatus 30 is energized, the open circuit voltage of the ballast transformer T is initially applied across gaseous discharge lamps L and the parallel combination of L and L The two lamps L and L are ignited thereby causing a current to flow through the lamps L L and the dropping resistor R The parallel circuit branch containing the gaseous discharge lamp L and the primary winding P presents a high impedance to current flow since the secondary winding S is essentially an open circuit. Since current flows through the resistor R the charging cycle of the capacitor C now commences. When the charge on capacitor C reaches a predetermined level, the reed switch 36 is activated, and the switching contacts 38, 39 close to cause the secondary circuit of transformer T to be shorted. Consequently, flasher transformer T; is in the low impedance condition, and lamp L is ignited and conducts current. The voltage across lamp L is now insufiicient to sustain the electric discharge and it flashes off.

When gaseous discharge lamp L conducts, it will be noted that the main load current in the secondary circuit of the ballast transformer T shunts the resistor R the extinguished lamp L being in effect an open circuit. Thus, during the interval that the gaseous discharge lamp L conducts, no charging current is supplied to capacitor C and it now discharges through the coil 37. When the voltage across coil 37 drops below a certain level, the switching contacts 38, 39 are again opened to restore the flasher transformer T to its high impedance condition, and another flashing cycle commences, the green and red lamp, L and L being alternately flashed on and ofi while the white lamp L operates at its normal and steady light output level.

The apparatus 30 is illustrated in FIGURE 2 was constructed for alternately flashing the red and green gaseous discharge lamps L and L at a flashing rate of one cycle per second. The following specifications of the circuit components used are given by way of a more specific exemplification of the invention and not by limitation thereof:

Transformer T 7,500 volt, .030 ampere, 225

vo-lt-amperes. Primary winding P 457 turns of .0339 inch in diameter wire. Secondary winding S 33,000 turns of .0031 inch in diameter wire.

Transformer T Rated at 27 volt-amperes.

Primary winding P 13,000 turns of .0028 inch in diameter wire.

Secondary winding S 400 turns of .021 inch in diameter Wire.

Resistor R 27 ohms, 1 watt.

Capacitor C 0.47 microfarad, 500 volts Reed switch GE reed switch rated at 15 volt-amperes.

Capacitor C S microfarads, 50 volts D.C.

Diode D 1Nl162.

Resistor R 2,000 ohms, 2 watt.

Coil 37 25,000 turns of .002 inch in diameter wire.

An important advantage of the apparatus 30 shown in FIGURE 2 is that gaseous discharge lamps L and L can 6 be alternately flashed on and ofl and one or more other lamps can be operated continuously from one ballast transformer with a switching element having a volt-ampere rating as low as 15 volt-amperes. This volt-ampere rating insures that the apparatus will provide a long and dependable service. For example, after 60 million flashing cycles, the apparatus 30 employing the specific circuit components described above was operating satisfactorily, and the reed switch 36 did not require any servicing.

Turning now to FIGURE 3, I have shown therein a schematic circuit diagram of an apparatus 50' for operating a pair of gaseous discharge lamps L and L at normal light output and for flashing a third gaseous discharge lamp L The starting and operating potentials for these lamps are supplied by a high leakage reactance type of ballast transformer T having magnetic shunts 51, a primary winding P and a high leakage reactance secondary winding 8 inductively coupled with the primary winding P on a magnetic core 52. The input terminals or leads 53, 54 of transformer T are provided for connection to a suitable alternating current supply. Gaseous discharge lamps L L and L are serially connected across leads 55, 56 and 57, gaseous discharge lamp L being connected across the primary winding P of the flasher transformer T As in the other illustrated embodiments of the invention, a secondary winding S of flasher transformer T is inductively coupled with a primary winding P on a magnetic core 58.

The switching means used in the embodiment of the invention to drive the flasher transformer T between a low impedance and a high impedance condition included a small synchronous clock motor 59 driving a rotary switch 60. The rotary switch 60 was comprised of a cam 61 and switching contacts 62, 63. Switching contact 63 is stationary while the other switching contact 62 is actuated by the pressure of the cam 61 as it rotates. The motor 59 is energized by the connections 64, 65 which are shown connected in circuit with input leads 53, 54 of the primary winding P It will be understood, of course, that the motor 59 may be directly connected to the alternating current at any convenient location, if desired.

With the apparatus 50 energized by connecting the input leads 53, 54 to an alternating current supply, the flashing rate of the gaseous discharge lamp L is controlled by the rotational speed of the motor 59 which drives the rotary switch 60. In general, the operation of apparatus 50 is similar to the apparatus 10 shown in FIGURE 1 except that the ballast transformer T must provide a sufficient starting and operating potential for three serially connected gaseous discharge lamps L L7 and L When the switching contacts 62, 63 are in the open position as shown, the flasher transformer T is in its high impedance condition, and gaseous discharge lamp L is flashed on. When the cam 61 rotates to a position in which the swi'ching contacts 62, 63 are actuated to a closed position, the secondary circuit of the flasher transformer T is shorted, and it is now in its low impedance condition thereby causing lamp L to flash off. The flashing rate can be readily changed by providing a motor having a different speed or by providing a variable speed motor or by a different number of tubes on the cam.

From the foregoing description it will be apparent that because of the low switching voltages which are made possible by the improved arrangement, the flashing apparatus can readily em-ploy various other types of switching arrangements. Although reed switches and a motor driven rotary switch are shown in the illustrated embodiments of the invention, it will be apparent that other switching arrangements can be used as for example, thermal switches, semiconductor switching circuits, and other switching arrangements that are rendered practicable because of the low switching voltages.

Although the gaseous discharge lamps are shown in the illustrated embodiments of the invention, as straight elongated tubes, it will .be understood that the lamps may be formed in any desired shape or configuration. For example, the lamps may take the form of words where the lamps are used in a sign to convey a desired advertising message.

While particular embodiments of the invention have been described herein for illustrative purposes, it will be apparent that these particular embodiments may be changed or varied without departing from the spirit and scope of the invention. It is to be understood, therefore, that I intend by the appended claims to cover all such modifications that fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An apparatus for flashing a gaseous discharge lamp from an alternaiing current source, said apparatus comprising: a high leakage reactance transformer for connection with the alternating current source to provide the starting and operating potential for said lamp, said transformer having a secondary winding for conneciion in circuit with the gaseous discharge lamp, a flasher transformer having a primary winding for connection in parallel with the gaseous discharge lamp, a secondary windin-g inductively coupled with the primary winding of said flasher transformer, and a switching means including a switching element connected across said secondary winding of said flasher transformer to alternately ope-n and close the secondary circuit thereof to flash said gaseous discharge lamp on and otf.

2. The apparatus set forth in claim 1 wherein the secondary windingof said flasher transformer is loosely coupled with the primary winding to limit the current flow through said switching element.

3. An apparatus for starting and operating gaseous discharge lamps from an alternating current source and for flashing at least one of the gaseous discharge lamps, said apparatus comprising: a high leakage reactance transformer for supplying the starting and operating potential for said gaseous discharge lamps, said high leakage reactance transformer having a primary winding for connection in circuit with the alternating current source and a secondary winding coupled thereto for connection in circuit with said lamps, a flasher transformer having a primary winding and a secondary winding inductively coupled therewith, said primary winding of said flasher transformer being arranged for connection in circuit with one of said gaseous discharge lamps, aswitching means including a switching element, circuit means connecting said switching element in circuit with said secondary winding of the flasher transformer to open and close the secondary circuit thereof during operation to thereby cause at least one of said gaseous discharge lamps to be flashed on and off.

4. The apparatus set forth in claim 3 wherein the secondary winding of said flasher transformer is loosely coupled with the primary winding to limit the current flow through said switching element.

5. An apparatus for starting and operating a plurality of gaseous discharge lamps from an alternating current source and for flashing at least one of said gaseous discharge lamps, said apparatus comprising: a ballast transformer having a primary winding for connection to the alternating current source and having a high leakage reactance secondary winding inductively coupled with said primary winding, circuit means including leads for connecting at least said high leakage reactance secondary winding in circuit with said gaseous discharge lamps to supply the starting and operating potential thereto, a flasher transformer having a primary winding and a secondary winding inductively coupled therewith, circuit means for connecting the primary winding of said flasher transformer in circuit with the gaseous discharge lamp to be flashed on and off during operation, and a switching means including a switching element connected in circuit with the secondary winding of said flasher transformer to cause said secondary circuit of said flasher transformer to be alternately opened and closed thereby to present a high and low impedance in circuit with said gaseous discharge lamp to be flashed on and off.

6. The apparatus set forth in claim 5 wherein the secondary winding of said flasher transformer is loosely coupled with the primary winding to limit the current flow through said switching element.

7. An apparatus for operating from an alternating current source a first gaseous discharge lamp at a normal light output level and for flashing a second gaseous discharge lamp, said apparatus comprising: a ballast transformer having a primary winding for connection to the alternating current source and having a high leakage reactance secondary winding coupled to said primary winding, circuit means for connecting the first and second gaseous discharge lamp in series across at least the secondary winding of said ballast transformer, a flasher transformer having a primary winding and a secondary winding inductively coupled therewith, means for connecting the primary winding of said flasher transformer in circuit across the second gaseous discharge lamp, and a switching means including a switching element operable between a low impedance and a high impedance condition, said switching means being connected in circuit with the secondary winding of said flasher transformer to short the secondary circuit and to open the secondary circuit thereof during operation thereby to cause the second gaseous discharge lamp to flash on and off.

8. An apparatus for operating a gaseous discharge lamp at a steady light output level and for alternately flashing a pair of gaseous discharge lamps, one of said pair of gaseous discharge lamps having a lower starting voltage than the other, said apparatus comprising: a ballast transformer having a primary winding for connection to the alternating current source and having a high leakage reactance secondary winding inductively coupled with said primary winding, circuit means for connecting one of said pair of gaseous discharge lamps to be flashed in a first parallel circuit branch and the other of said lamps in a second parallel circuit branch and for connecting said parallel circuit branches in a series circuit with the gaseous discharge lamp to be operated at a steady light output level, means connecting said series circuit across said secondary winding, a flasher transformer having a primary winding and a secondary winding inductively coupled therewith, said primary winding being adapted for connection in the parallel circuit branch with the gaseous discharge lamp having the lower starting voltage and in series circuit relation therewith, and a switching means including a switching element operable between an open and closed condition at a predetermined frequency, said switching element being connected in circuit with the secondary winding of the flasher transformer to open and short the secondary circuit thereof, and said switching element when switched from the open to the closed position causing one of said pair of gaseous discharge lamps to flash on and the other of said lamps to flash off.

9. An apparatus for flashing at least one gaseous discharge lamp and for operating at least one gaseous discharge lamp at a steady light output level, said apparatus comprising: a ballast transformer having a primary winding and a high leakage reactance secondary winding inductively coupled therewith, circuit means connecting said ballast transformer in circuit with said lamps for supplying the starting and operating potentials thereto, a flasher transformer having a primary winding and a loosely coupled secondary winding, circuit means for connecting the primary winding of said flasher transformer in circuit across one of said lamps, and switching means including a switching element switchable from an open to a closed condition at a predetermined frequency, said switching element being connected across the secondary winding to short and open the secondary circuit of said flashing transformer thereby to cause the gaseous discharge lamps connected across the primary winding of said flasher transformer to be flashed on and off.

10. The apparatus set forth in claim 9 wherein the switching means is comprised of a motor and a rotary switch operatively connected as said switching element, said rotary switch being driven by said motor at a predetermined frequency to short and open the secondary circuit of said low leakage reactance transformer.

11. An apparatus for operating at least one lamp at a steady light output level and for alternately flashing a pair of gaseous discharge lamps on and oif, one of said flashing lamps having a lower impedance than the other of said pair of flashing lamps, said apparatus comprising: a ballast transformer having a primary winding for connection to an alternating current source and a high leakage reactance secondary winding inductively coupled therewith, circuit means for connecting at least said high leakage reactance secondary winding in circuit with the gaseous discharge lamps for supplying the starting and operating potential thereto and for connecting one of the pair of flashing lamps in a first circuit branch and for connecting the other of the pair of flashing lamps in a second circuit branch connected in parallel with the first circuit branch and in series circuit relation with the lamp operated at a steady output level, a reactive device having a first winding and a second winding inductively coupled therewith on a magnetic core, circuit means for connecting said first Winding in series circuit with the flashing lamp in said first circuit branch, and a switching means including a switching element connected in circuit with the second winding of said reactive device, said switching element when closed actuating said reactive device from a high impedance to a low impedance condition to flash on the gaseous discharge lamp in the first circuit branch and to flash off the gaseous discharge lamp in the second circuit branch, and said switching element when opened actuating said reactive device from the low impedance condition to the high impedance condition to flash off the gaseous discharge lamp in the first circuit branch and to flash on the gaseous discharge lamp in the second circuit branch.

References Cited by the Examiner UNITED STATES PATENTS 2/1939 Batchelor 315-255 X 9/1951 Seaman 315186 X 

1. AN APPARATUS FOR FLASHING A GASEOUS DISCHARGE LAMP FROM AN ALTERNATING CURRENT SOURCE, SAID APPARATUS COMPRISING: A HIGH LEAKAGE REACTANCE TRANSFORMER FOR CONNECTION WITH THE ALTERNATING CURRENT SOURCE TO PROVIDE THE STARTING AND OPERATING POTENTIAL FOR SAID LAMP, SAID TRANSFORMER HAVING A SECONDARY WINDING FOR CONNECTION IN CIRCUIT WITH THE GASEOUS DISCHARGE LAMP, A FLASHER TRANSFORMER HAVING A PRIMARY WINDING FOR CONNECTION IN PARALLEL WITH THE GASEOUS DISCHARGE LAMP, A SECONDARY WINDING INDUCTIVELY COUPLED WITH THE PRIMARY WINDING OF SAID FLASHER TRANSFORMER, AND A SWITCHING MEANS INCLUDING A SWITCHING ELEMENT CONNECTED ACROSS SAID SECONDARY WINDING OF SAID FLASHER TRANSFORMER TO ALTERNATELY OPEN AND CLOSE THE SECONDARY CIRCUIT THEREOF TO FLASH SAID GASEOUS DISCHARGE LAMP ON AND OFF. 